The present invention relates generally to lifting equipment such as cranes which use high-strength fiber ropes. The invention here in particular relates to an apparatus for monitoring operating data and/or for determining the replacement state of wear of such a rope in use on such lifting equipment having a detection device for detecting at least one rope use parameter that influences the replacement state of wear and having a data store for storing the detected rope use parameter and/or an operating parameter derived therefrom that characterizes the residual service life and/or the replacement state of wear of the rope.
In recent times, trials have been made with cranes to use high-strength fiber ropes made from synthetic fibers such as aramid fibers (HPMA), aramid/carbon fiber mixtures, high-modulus polyethylene fibers (HMPE) or poly(p-phenylene-2,6-benzobisoxazole) fibers (PBO) instead of the proven steel ropes used for many years. The advantage of such high-strength fiber ropes is their low weight. Such high-strength fiber ropes are considerably lighter than corresponding steel ropes at the same rope diameters and the same or higher tensile strength. In particular with high cranes with correspondingly large rope lengths, a greater weight saving is hereby achieved which enters into the dead-weight load of the crane and results in correspondingly higher payloads with an otherwise unchanged construction design of the crane.
A disadvantageous property of such high-strength fiber ropes is, however, their break behavior or their failure without substantial, longer preliminary signs. Whereas the wear is clearly visible in steel ropes and signals a failure over a longer period in advance, for example by the breakage of individual steel wires and a corresponding splaying which is easily noticed, high-strength fiber ropes show hardly any signs of excessive wear which would be easily perceivable for the eye and which would show themselves clearly over a longer period before the actual failure. In this respect, intelligent monitoring measures are required to recognize the replacement state of wear of high-strength fiber ropes in time.
A fiber rope is known from the document US 2015/0197408 A1 in which an indicator strand is embedded, in addition to the fiber bundles transmitting the tensile strength, that is configured as comparatively weaker and that should in every case break before the complete rope failure to provide an advanced warning signal. The indicator strand here has a test signal applied with the aid of an RFID chip and its forwarding or return is impaired on a break of the indicator strand, from which a conclusion can then be drawn on the replacement state of wear. This already known rope admittedly provides a kind of advance or early warning system. However, it is not possible to say how far the rope still is from the replacement state of wear or how far the rope has progressed in its service life or load duration before reaching the replacement state of wear that is shown by break of the indicator strand.
A rope in which an RFID chip is embedded is likewise known from the document DE 10 2012 105 261 A1. Specific manufacturer data such as the batch, the raw materials used, and the stranding speed or stranding date should here be stored in said RFID chip during manufacture during stranding to then be able to draw conclusions on the manufacturing conditions on a later break of the rope or generally on problems with the rope. Due to the previously mentioned influences on the service life of a rope, that differ greatly in dependence on the deployment site and on use and that can result in too great a variance of the actual service life, it is, however, practically not possible to precisely predict the actual replacement state of wear from said data of the rope stored on the manufacturer's side, which, in particular with fiber ropes, can result in an unforeseeable failure or conversely, on a worst-case determination, in a wasting of a fairly large part of the typical service life.
Document U.S. Pat. No. 8,912,889 B2 describes an electrical power cable in which an RFID chip attached to the cable is used to determine the rotation or torsion that occurred during laying or when coiling and uncoiling.
It is to this extent ultimately not reliably and precisely possible with the aforesaid rope systems also to be able to predict the replacement state of wear of a rope under different operating conditions and to be able to analyze a case of damage with reference to the operating conditions. Systems have already been proposed in this regard by means of which operating parameters of lifting equipment such as load hoists and bending cycles can be monitored to be able to draw conclusions on the service life of the system from them.
An apparatus is known from DE 199 56 265 B4 for monitoring the operation of hoist winches on cranes which monitors the rope force of the hoist rope and the lever arm of the hoist rope on the rope winch and determines therefrom the load cycles acting on the rope winch which are stored in a load spectrum counter. This load spectrum counter is integrated into the hoist winch to maintain the history of the hoist winch retraceably on a removal and reinstallation of the hoist winch. A load spectrum counter is furthermore known from EP 0 749 934 A2 which determines the load changes which occur, determines the rope force acting on the hoist winch at each load change, calculates the load spectrum therefrom and calculates and displays the remaining service life of the hoist winch while considering the so-called Wöhler curves.
Such monitoring measures of the hoist winch can, however, not really reliably indicate the remaining service life or the replacement state of a high-strength fiber rope since the high-strength fiber ropes are subject to a variety of strains and impairments which influence the wear and which are independent of the winch strain, for instance e.g. the deflection and bending strains at deflection pulleys external blows and buffets on the rope, surface contamination of components contacting the rope, etc. On the other hand, inflexible service life standards for high-strength fiber ropes are practically incompatible with respect to economic utilization of the actual service life and observation of the required safety since the service life and wear of the high-strength fiber rope can fluctuate strongly in dependence on the conditions of use and on the external influences on the high-strength fiber rope.
It is furthermore known from WO 2012/100938 A1 to monitor a plurality of rope parameters of a high strength fiber rope that indicate characteristic changes when approaching the replacement state of wear. Even if a rope parameter does not show any change or any significant change or any sufficiently strong change, the replacement state of wear can be recognized by monitoring further rope parameters, in particular when a plurality of parameters show changes. The detection device of the apparatus for recognizing the replacement state of wear here comprises a plurality of differently configured detection means for the magnetic, mechanical, optical, and electronic detection of a plurality of different rope parameters that can be evaluated individually and/or in combination with one another by the evaluation unit to recognize the replacement state of wear. Despite the evaluation of a plurality of parameters, however, the problem remains that the replacement state of wear is not always actually present with the same rope parameter changes or there is no fixed connection between individual rope parameter changes and the replacement state of wear. Depending on the individual case, for example, a different meaning for the replacement state of wear can accrue to a change in lateral pressure stiffness or to a number of bending interplays.
Starting from this, it is the underlying object of the present invention to provide an improved apparatus for monitoring the operating influences relevant to the replacement state of wear of high-strength fiber ropes which avoids disadvantages of the prior art and further develops the latter in an advantageous manner. A reliable, precise determination of the replacement state of wear should preferably be made possible which economically utilizes the remaining service life of the fiber rope and which permits the use of the rope on different pieces of lifting equipment without putting safety at risk and managing for this purpose with simple detection devices which also operate reliably under difficult conditions of use for construction machinery.
This object is achieved in accordance with the invention by an apparatus in accordance with claim 1. Preferred embodiments of the invention are the subject of the dependent claims.
It is therefore proposed to monitor rope use parameters and/or operating parameters relevant to the service life of the rope and/or to its replacement state of wear during the use of the rope on the lifting equipment and to store these rope use data or the operating parameters derived therefrom that relate to the operating life and/or replacement state of wear of the rope directly in the rope. Storing operating data that characterize the rope use and/or its effect on the residual service life of the rope directly in the rope has the great advantage that the residual service life or the replacement state of wear of the rope can also be precisely determined when the rope is removed from the lifting equipment and is reinstalled on a different piece of lifting equipment since the rope so-to-say takes along “its” use data and can provide them again to the new lifting equipment and to its evaluation and monitoring devices. Provision is made in accordance with the invention that the data store for storing the at least one detected rope use parameter and/or an operating parameter derived therefrom is integrated in the rope, with a reading and/or writing unit connected to the detection device for detecting said rope use parameter being provided to write to the data store in the rope installed at the lifting equipment. Said reading and/or writing unit is therefore configured and provided to write to the data store integrated in the rope while the rope is used on the lifting equipment or is in its state installed at the lifting equipment in accordance with its intended purpose. The rope use parameter or the operating parameters determined therefrom are stored in the rope or in the data store provided there while the rope is on the lifting equipment.
Said writing and/or reading unit can be installed at the lifting equipment in an advantageous further development of the invention and can communicate with different ropes to this extent. If, for example, a rope ready for replacement is removed and replaced with a new rope, the reading and/or writing unit can also communicate with the new rope.
The rope use parameters stored in the rope can be read out again at a new piece of lifting equipment and can be used by the control and/or evaluation unit of the new piece of lifting equipment to precisely monitor the rope use and the replacement state of wear possibly resulting therefrom when a rope is removed and is installed on another crane. The operation of the lifting equipment can additionally also optionally be blocked if the replacement state of wear has already been stored in a rope and this rope that is to be discarded is accidentally again installed at a new piece of lifting equipment. It can hereby be reliably prevented that ropes that are ready for replacement per se are accidentally used again.
Alternatively or additionally to such a reading and/or writing unit provided at the lifting equipment side, it would, however, also be conceivable to provide a reading and/or writing unit at the rope itself and to communicationally connect it to the detection device for detecting the at least one rope use parameter.
In a further development of the invention, the reading and/or writing unit and the data store can be configured to communicate wirelessly with one another. The data that are written to the data store can be transmitted wirelessly from the reading and/or writing unit to the data store. Conversely, provision can also be made that the data can be wirelessly read out of the data store.
An RFID element can in particular be integrated in the rope as a data store, with in this case the reading and/or writing unit being able to have a radio transmitter and/or a radio receiver, in particular a radio frequency transmitter and radio frequency receiver.
Alternatively or additionally to such an RFID chip, the data store can also comprise other storage means, for example in the form of a remotely readable RAM memory.
It must be noted that separate units can generally be provided for writing to the data store integrated in the rope and for reading the data out of it, for example in the form of a simple writing unit, on the one hand, and a simple reading unit, on the other hand, with it also being able to be sufficient if only the operating data are to be documented to be able to work with a reading unit and only to be able to write data to the data store. However, a reading and writing unit is preferably provided that can both write data to the data store and read data from it.
Said reading and/or writing unit can be directly connected to the detection device that detects the at least one rope wear parameter to be able to store the relevant detected rope use data directly in the data store. Alternatively or additionally, an indirect connection to the use data detection can also be provided, in particular via a control and/or evaluation device that evaluates the detected rope use parameter and determines an operating parameter derived therefrom, for example the residual service life and/or the percentage of the replacement state of wear reached. Such derived operating parameters such as the residual rope operating hours can advantageously be stored in the data store at the rope in addition to the rope use parameters that were directly detected by the detection device. In addition, rope identification data and/or manufacturing data such as the manufacturer batch, stranding characteristics, et cetera can be stored in the data store.
The reading and/or writing unit can generally effect the storage of the data in said data store of the rope and/or the reading of the data therefrom in different manners, for example every time the lifting equipment, for example the crane, is put into operation or shut down. Alternatively or additionally to such a writing/reading at the start and end of an operating phase, the reading and/or writing unit can also be configured such that the detected rope use parameters and/or the operation parameters derived therefrom are cyclically written to the data store of the rope and/or are read out therefrom at predetermined time intervals.
In a similar manner, the reading and/or writing unit can transmit data read out of the data store to a control and/or evaluation device of the lifting equipment, for example in the aforesaid manner in each case at the start or end of an operating phase, in particular on switching on of the lifting equipment and on a shutting down of the lifting equipment and/or in said cyclic manner at temporally predefined intervals. The control and/or evaluation device can then transmit the rope use parameters and/or the operation parameters derived therefrom by remote data transmission, for example, in this manner to a service and/or monitoring station by means of which the operation of the lifting equipment can be remotely monitored and/or remotely serviced.
To enable a reliable, simple data transmission between the data store at the rope and the reading and/or writing unit at the lifting equipment, said reading and/or writing unit and the data store are arranged at spatial proximity in an advantageous further development of the invention. Provision can advantageously be made for this purpose that the data store is integrated in said rope at a rope end section.
In a further development of the invention, the data store can be provided at a rope end that is lashed to a hoist winch, with in this case the reading and/or writing unit advantageously being able to be attached in the region of the hoist winch, in particular at the hoist winch itself. In an advantageous further development of the invention, said reading and/or writing unit can be attached to a guard plate of the drum onto which the rope is wound. It can in particular be advantageous here if the data store is integrated in a rope end section that is end-fastened in the region of said guard plate, for example by means of rope clamps, rope locks, or an end fastening bollard about which a spliced rope eye can be laid.
Alternatively or additionally to such an arrangement of the data store and the reading and/or writing unit at a hoist winch, the data store can also be provided at fixedly lashed end section of the rope, with in this case the reading and/or writing unit advantageously being able to be installed at a structural part of the lifting equipment to which the fixed rope end is lashed or fastened.
The at least one rope use parameter detected by the detection device can generally be of different kinds.
For example, environmental influences and/or weather data to which the rope is exposed when the rope is on the crane can be detected as the rope use parameter and/or as the operation parameter that are relevant to the determination of the replacement state of wear, with the crane operating times and/or down times being able to be taken into account. The detection device advantageously has at least one detection means for detecting environmental influences on the rope that can be evaluated by the evaluation device to recognize the replacement state of wear and are stored in the data store of the rope by the reading and/or writing unit.
Different environmental influences can be relevant and detected to this extent here. For example, particles such as dust, sand, or rust deposited at the rope and/or at the rope drum can result in an increased chafing strain on the rope surface and can hereby accelerate the replacement state of wear. In a further development of the invention, the aforesaid detection means can have a particle detector for detecting the dirt particles present in the environmental air. The evaluation device can then determine the replacement state of wear of the rope in dependence on the dirt particle quantity and/or dirt particle property detected over time.
Alternatively or additionally to the aforesaid environmental influences, the aforesaid detection device can, in a further aspect of the present invention, also have a weather station for detecting weather data to which the crane or the rope provided thereat is exposed and in dependence on which the evaluation device determines the replacement state of wear. Said weather station can here detect different climatic situations that can influence the service life of the rope, for example the temperature and/or the UV radiation and/or the amount of precipitation and/or the precipitation profile and/or the humidity and/or water and/or salt water and/or snow and/or ice that can be stored in the data store at the rope by the reading and/or writing unit.
The evaluation device can here be configured such that it processes one or more of the aforesaid rope use parameters and takes them into account in the determination of the replacement state of wear. The replacement state of wear can, for example, be determined earlier if the rope is frequently exposed to very low and/or very high temperatures and/or is used at very low and/or very high temperatures, that is, it is exposed to loads and is subject to bending cycles. Alternatively or additionally, the replacement state of wear can, for example, be determined earlier if the crane is used in very high radiation environments; that is, the rope is exposed to high UV radiation that can make high strength fiber ropes brittle earlier. Alternatively or additionally, high precipitation rates and/or high moisture and/or greater amounts of snow and ice can be used for a shortening of the service life or for an earlier output of the signal of a replacement state of wear. Alternatively or additionally, it can also be taken into account that salt water at the rope, for example at maritime deployment locations or also the action of water on the rope, for example on uses at deep sea platforms or at rivers, can shorten the service life.
The detection device preferably additionally or additionally to the aforesaid determination means for the weather or for environmental influences comprises a plurality of differently configured detection means for a magnetic, mechanical, optical and/or electronic detection of a plurality of different rope parameters which can be evaluated by the evaluation unit individually and/or in combination with one another for recognizing the replacement state of wear. The use of different rope parameters such as the aforesaid environmental data or weather data or mechanical rope parameters such as the lateral pressure stiffness and cross-sectional change or, alternatively or additionally thereto, a rope lengthening and magnetic rope properties or other mechanical, optical and/or electronic rope parameters for the determination of the replacement state of wear is based on the consideration that depending on the strain and on the effects on the fiber rope, it may from case to case be a different parameter which displays the rope wear or signals the replacement state of wear or the replacement state of wear may also not display itself by an actually larger change of only a single parameter, but rather by smaller changes of a plurality of parameters.
In a further development of the invention, the named evaluation unit is configured such that a replacement signal is provided when at least one of the detected rope parameters or its change exceeds/falls below an associated limit value and also when an indirect rope parameter or its change derived from all detected rope parameters or from a subgroup of the detected rope parameters exceeds/falls below an associated limit value.
In addition to said rope use parameters relating to the environmental influences to which the rope is exposed and/or the weather data present on the use, the system can in particular also take account of the load spectrum acting on the rope and/or of the bending cycles that occur and can store them in the rope. In this respect, the tensile loads acting on the rope and/or the bending cycles acting on the rope can be used as the load spectrum acting on the rope for the determination of the replacement state of wear of the fiber rope. A load spectrum counter can be provided for this purpose which detects at least the tensile rope stress and the number of bending cycles as the load spectrum acting on the fiber rope. The determination and evaluation of the named measured data is possible via corresponding determination means or detection means or sensors whose measured data are processed and evaluated in the evaluation device. A load sensor can in particular detect the ongoing strain of the rope via the operating time of the rope. A rotary encoder on the drum of the rope winch can determine the rope length which is strained to determine the bending cycles. The load data and the data on the rope path and on the bending cycles can be linked to one another in the evaluation device to determine a load spectrum which can be compared with a predefined permitted maximum load spectrum. If the number of the maximum permitted load spectrum is reached, the evaluation unit can output a corresponding replacement signal.
In a further development of the invention, different other rope parameters can be used in addition to the parameters on the environment and on the weather, for example a change of the lateral pressure stiffness or of the rope cross-section. The detection device for detecting rope changes can in particular have lateral pressure stiffness determination means and/or cross-sectional determination means for determining the lateral pressure stiffness or the rope cross-section, wherein the evaluation unit monitors the lateral pressure stiffness or the determined rope cross-section for changes and provides a replacement signal as necessary.